Katy Perry, Usher, Play for Military Kids at Inaugural Concert

Obama and Biden took the stage near the end, calling in groups of military kids on video chats broadcast on the big screens. The first lady in particular was earnest in her words, appealing to all ages.

"You see, when we said we wanted to host a concert to honor our military kids, let me tell you, everyone wanted to be here. Usher wanted to be here," she said. "Katy Perry wanted to be here. Nick Cannon, the folks from 'Glee,' and all the other amazing performers -- they wanted to be here, too. And let me tell you, they're not here for me. They're not here for Dr. Biden. They are here for all of you. Because they know the kind of sacrifices that you all make every single day."